Turkish police raided at least 16 addresses across Istanbul overnight, including an apartment in a conservative neighbourhood, where a cab driver said he picked up the three men suspected in Tuesday’s terror attack.

The unnamed taxi driver who drove the attackers to Ataturk Airport said the men spoke in a language he didn’t recognize.

Erdal Simsek told CTV’s Tom Walters that he recently fixed a tap in the men’s apartment.

Simsek said he felt as if the men were watching him the whole time and that it seemed like they couldn’t get rid of him fast enough.

He also said the men spoke a language he didn’t recognize.

“And the whole place smelled like gas,” Simsek added.

A senior Turkish official who spoke on the condition of anonymity said the attackers were from Uzbekistan, Kyrgyzstan and Russia. The official said the men crossed into the country last month from the ISIS-controlled city of Raqqa, Syria.

The International Centre For The Study Of Radicalisation And Political Violence estimated in 2015 that 3,000 of an estimated 20,730 foreign fighters in Syria and Iraq were from former Soviet republics like Uzbekistan (500), Kyrgyzstan (100) and Russia (800 to 1,500).

With a report from CTV’s Tom Walters in Istanbul and files from The Associated Press